ROCKTON, Ill. (AP) — Emergency crews are battling a massive fire at a northern Illinois chemical plant that exploded into flames.

The Monday morning explosion that sent huge plumes of thick black smoke into the air prompted officials to order an evacuation of residents and business to the south of Chemtool Inc., near Rockton.

There were no immediate reports of injuries. The plant that manufactures grease products, lubricants and other fluids. Rockton is located in Winnebago County, near the Wisconsin border, about 95 miles northwest of Chicago.